Measuring instrument



July 17, 1928.

W. JANDUS {IEASURING INSTRUMENT Filed Oct. 7. 9

m VE NITOR 4M-%drm 'sessed by coils of very with suitable means and mountings to l atented July 17, 1.923.

UNETQQ STATES PATENT OFFICE.

WILLIAM JANDUS, OF EASTCLEVELAND, OHIO, ASSIGNOR OF ONE-HALF T0 HERBERT S. JANDUS, OF DETROIT, MICHIGAN.

MEASURING INSTRUMENT.

Application filed October 7, 1921. Serial No. 506,221.

My invention relates to c a method of translating rectilinear motion into rotary movement without friction. Its functional feature depends upon the properties posthin ribbon steel or other resilient substance to torsionally wind or unwind when subjected to varying longitudinal stresses. Its mechanical feature depends upon structural *means for producing the greatest amplitude of rotary movement with the shortest rectilinear motion and upon suitable means for communicating the rotary function to an operating mechanism. Further and more limited objects of my invention'will appear as the description proceeds and by reference to the accompanying drawing in which Fig. 1 is a view in side elevation of one form of a helicoid spring used in my measuring instrument; Fig. 2 is a perspective View of a modification of my device and Fig.3 is a perspective View showing a still further modification of my invention as used in a mechanical thermometer.

The invention consists in mounting the needles of measuring instruments on helicoid springs of ribbon steel orof other highly resilient substance said springs being provided hold them flexibly to their supports and to their sources of operating power.

By the direct translation of rectilinear movement into rotary motion, the indicating I and recording needles of measuringinstruments may be operated without friction and without the conventional spindles. jewelled bearings, belts, drums and reciprocating springs. The needles are connected up directly to the operating power which when applied to the spring, proceeds to unwind it, carrying axial movement. Released from the longitudinal stress, the coil resumes the normal position carrying the needle back to the starting point. p

Fig. I in the drawing is an elevational view of a helicoid spring H made of thin ribbon steel or other resilient material the upper end of which terminates in a straight, flexible ribbon R made of similar material, the lower end being provided with a mounting M. The ribbon B being fixed to a suit-- able support and the mounting M to a source of power, the locus of rotation will be found at the juncture of the coil and the ribbon J. Fewer being to the M the needle in the direction of theco1l H proceeds to unwind communicating vits movement of rotation to the juncture J through a torsional twisting of the ribbon R.

In Fig. II is shown a modification of the helicoid devicedescribed. In this form both the upper andlower end of the coil terminate in straight, flexible ribbons R, It. The spring is held in tension by the frame V at I, J the junctures of rotation. A needle N 1s secured to the upper part of the frame V the projection WV at the lower end being a counterweight to the needle. In the middle of the coil is a mounting M for engaging the forked lever L flexibly hinged to the frameU by a thin sheet spring S. The terminal ribbons R, R are secured to a support U at X, X. In the drawing theribbons are supposed to be soldered to the arms of the support U as shown at G. Normally, the lever L is flexed by the spring S so as to compress the lower part of the helix H and thus to elongate the upper part H thereby rotating the needle away from the zero position in one direction on the scale D. By applying a source of power F to the pin P at Z the upper part H is compressed and the lower part H is correspondingly elongated thus reversing the movement of the needle. In the drawing the force F is supposed to be just suflicient to hold the needle on the zero point of the scale D.

Fi III shows an application of the helix described. in Fig. I in a mechanical thermometer. B is a base on which are mounted a support U and a block K. To the latter is fixed a thermic element T made of thermostatic metal designed to flex by temperature. The helicoid spring H is attached to the thermic element T at the point M and the flexible ribbon R to the frame U at the point M. A needle N counterweighted at. IV and registering angular movements on a dial D-is fixed to the juncture of rotation J. The thermic element T is slotted longitudinally at I and in the groove so produced a sliding nut E is guided by the screws A and C threaded into it. Normally the thermic element T is flexed to bend downward so as to touch the floor of the base atits extreme end 'M if unsupported. The regulating screw A whichpasses through the nut E to the floor of the base B prevents this. By means of this screw the element T may be raised or lowered in respect to said base and the'needle moved any point of:

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I per'ature will contract the coil H and the scale D. The distance between M and the point of contact of the regulating screw A with the floor of the base 13 determines the effective operating length of the element Ti and hence its scope of action. The greater the distance the greaterthe sensitiveness and the greater the deflection of the needle. Hence by moving the sliding nut less neutral to expansion and contraction by temp rature. The upper surface is made of brass having a definite rate of expansion by ten'iperaturel together; A rise of temperature will expand the brass surface and move the point d of the thermic element downward thus stretching the coil H which will relieve the rectilinear strain by unwinding, thereby producing a torsion in the ribbon R and moving the needle to the right. A drop in tem- Pr duce a reverse movement of the needle.

As in the devices herein described, so in all other measuring devices such frictionless mounting of needles maybe made to super sede the conventional mode. of suspension,

Having described my invention What I claim as new is;

1. A device of the class described comnected adjacent the juncture .of said QX- tension and spring and means operatively connected with said spring at a point removed from sald uncture and wlth said base member for causing a rectilinear distort-ion of said spring and an angular defiection of said needle in a single lane.

2. A device of the class describec compris- The two metals are welded end connected with said frame, said lever serving as a means for tensioning said spr ng. r c

3. A measuring instrument of the class described comprising a base member, a support extending from said base member, a helicoid spring having a ribbon extension fixedly secured to said support, indicating mechanism including a scale 'and a pointer, said pointer being secured at the juncture of said extension and spring, a lever having one end connected with said spring at a p'ointremoved fiom said juncture and its opposite end connected with said base member and serving as a means for causing a rectilinear distortion of said spring and'an angular ClQfiGC- tion of said pointer.

4. An instrument of the character described comprising a base member, support frame rising from said base member, a helicoid spring having a ribbon extension fixedly secured to said frame, indicating mechanism including a scale and a pointer, said pointer being fixedly secured adjacent said juncture, a flexible thermic element hav ing one endfixedly secured to said spring at a point remote from said juncture and opposite end connected with said base memher, said thermic element serving as a means for causing a rectilinear distortion of said spring and an angular deflection of said needle. a

5. A device as set forth in claim 4 having means for varying the te-nsion of said thermic element. r 7

6. A device as set forth in claim t having means for varying the elfectivelength of" said thermic element and in which said i pointer is provided with a counterwieght.

WILLIAM James; 

